Southern Ocean Eco-systems

The inaugural lecture for Professor Steve Wing from the Department of Marine Science.

Reefs have waves in the sea itself. Where the water from the ocean hits the continental shelf it causes turbulence which rushes onto the edge of a reef. This introduces organic matter to the reef. Organic matter matters a lot in marine eco-systems. This starts to get interesting right about now.

Populations can be “closed”, like a herd of cattle in a paddock; or “open”, like an eco-system. An eco-system can appear to be closed and expansion of the population in the environment can spread it out into an open system.

Human exploitation affects marine population. We tend to eat them out. Open populations are more robust against human exploitation. A refuge for the stock can replenish the population and benefit the fishing industry.

At this point I find myself thinking that this is a great argument for the Maui’s Dolphin Marine Reserve: Save a threatened species and quarantine fishing grounds as a reserve that can become supply for the fishing industry.

Then there’s Fiordland. The fiords vary in salt water levels and physical arrangement. The fertile mouths of the fiords open to the sea re-populate the inner fiords. Exploitation can destroy populations. So the responsible government minister, Pete Hodgson at the time, pushed through legislation that only recreational fishing is allowed on inner-fiord populations. They have become areas of refuge. The exploited species have bounced back creating more, mature populations. The marine reserves now show 8 times the level of fecundity, restoring a stable predator population in the kelp environments.

What does the bear do in the wood? Nitrogen from its seasonal salmon-rich diet replenishes the British Columbian forests. If fish is good for the brain then that is a lot of intelligent trees after thousands of years of salmon migration! Penguins do the same in the sub-antarctic islands. New Zealand lies in the zone where sub-tropical waters meet the iron-rich waters of the sub-antarctic ocean. The predators have the greatest concentration of iron from the meeting of these waters. It would benefit the environment of the ocean if pigs could be removed from the Auckland Islands and these could be reclaimed as nesting colonies for sea birds.

That zone where the sub-tropical waters and the sub-antarctic waters meet could shift due to climate change. The New Zealand economic zone covers 9% of the earth’s surface. We are responsible for that. We need to pay attention to the state of the Southern Ocean Eco-system, including the Ross Sea, the last intact eco-system. It’s part of our household.

The Hagfish, just one of the many interesting things you can find in a fiord!